Use the latest scientific techniques to poke a hole or two in official findings on the Kennedy assassination and suddenly you have lots of new friends - and lots of enemies.

Dr. Cliff Spiegelman of Texas A&M University is the leader of a team of scientists who investigated bullets from the same manufacturing lot as those used by Lee Harvey Oswald during the assassination of JFK in 1963.

Forty-five years after President John F. Kennedy was killed in a Dallas motorcade, the details surrounding his death remain topics of endless debate for those who see conspiracies and those who disagree.

Cliff Spiegelman will testify to that.

The professor of statistics at Texas A&M University organized a six-member team that compared the composition of bullet fragments from the JFK shooting with other bullets from the same manufacturer.

The group found that those fragments weren't nearly as rare as the government's expert witness concluded in 1976, when Dr. Vincent P. Guinn determined that all five fragments came from two bullets fired by Lee Harvey Oswald. A third shot missed.

"The claim was made that those five fragments could only have come from two bullets," Dr. Spiegelman said. "Our research showed it could have been two or more.

"And if it is more than two, there is an increased likelihood that someone else provided one of them."

Many of the test bullets showed the same "chemical composition," and one matched fragments from the assassination bullets, he said.

Hence the title of the group's paper: "Chemical and Forensic Analysis of JFK Assassination Bullet Lots: Is a Second Shooter Possible?" The team was honored by the American Statistical Association with its 2008 Statistics in Chemistry award.

The study doesn't say there were two or more gunmen, only that the single-gunman theory can't be supported by science.

Naturally, that triggered "a bit of a buzz," said Gary Mack, curator of The Sixth Floor Museum at Dealey Plaza.

"The no-conspiracy folks, they accepted [Dr. Guinn's] analysis without too much questioning," Mr. Mack said. "But others wondered whether he knew what he was talking about. And the sharp ones were very skeptical that [the one-shooter findings] could be so definitive."

By allowing the possibility of multiple gunmen, the study quickly made the rounds on Internet sites and conspiracy bulletin boards.

"Do a search of 'Spiegelman and JFK' and see how many hits you get," Dr. Spiegelman said. "Depending on the day, it's somewhere between 50,000 and 90,000."

Many readers passed along their own theories.

A minister who had served in Central America told him that a former member of the mob confessed that he helped plan the assassination, Dr. Spiegelman said.

"I got a letter that said, 'Hey stupid, we had a coup. [Lyndon] Johnson did it.' "

A phone message from Australia promised to reveal the real killer only if Dr. Spiegelman called back.

And an elderly gent from West, Texas, said he found a weapon like Mr. Oswald's Carcano rifle in a hotel the day after the assassination. Would Dr. Spiegelman like to see it?

At the same time, others attacked details of the study, citing things like the bullets' manufacturer, mentioned at one point as Winchester, then as the Western Cartridge Co.

Stuart Wexler, a 32-year-old teacher from New Jersey, joined the team and provided the test bullets, acquired during a two-year search of eBay auctions, shooting sites and online newsgroups.

"Finding those bullets was incredibly tough," Mr. Wexler said. "There are a lot of Carcano rounds out there, but not a lot of Western Carcano rounds."

Yes, they were made by Western, which acquired Winchester in 1931, he said.

Even now, a year after the study's publication, Mr. Wexler is amazed at the response.

"There was a tremendous amount of buzz," he said. "Unfortunately, a number of the international headlines overstated our conclusions. Some of it was almost pure propaganda."

It reminded him of something he saw recently on the Onion, a satirical Internet site, in its summary of the news of 1963:

"Kennedy Slain by CIA, Mafia, Castro, LBJ, Teamsters, Freemasons. President shot 129 Times from 43 Different Angles."